Phase behaviour of dipalmitoylphosphatidylcholine/surfactant/water systems studied by infrared spectroscopy

Phospholipids are the most important components of membranes taking part in stabilization of the functional structure of biological cells. The main aim of the present study is to determine the influence of selected antimicrobial surfactants on the phospholipids structure. The water solutions of dipalmitoylphosphatidylcholine (DPPC) in the presence of two quaternary ammonium surfactants: dodecyldimethyl(hexyloxymethyl)ammonium chloride (HMDDAC) and (decyloloxymethyl)dodecydimethylammonium chloride (DMDDAC) were studied using FTIR spectroscopy. The thermal behaviour of these systems was analyzed using spectral parameters of CH2 and CO vibrations bands. We have observed a lowering of temperature corresponding to the main phase transition of the surfactant/DPPC systems due to disordering of the phospholipids structure by the surfactants and phospholipids interaction.